1904] 



Studies on Enzyme Action, 



517 



Historical. — The observation made by Wiirfczin 1879,* when studying 

 the action of Papain on fibrin, that the enzyme was in some way 

 retained, probably first gave rise to the conception that the primary 

 action of enzymes was additive in character. The first definite evidence 

 of combination, however, appears to be that advanced by O'Sullivan 

 and Thomson in 1890. f It was shown by these observers that in the 

 presence of cane sugar invertase will withstand without injury a 

 temperature fully 25° higher than it will in its absence. They pointed 

 to this as a very striking fact which was difficult to explain except on 

 the assumption that the invertase enters into combination with the 

 sugar; they further supposed that it was capable of combining with' 

 the invert sugar. 



Systematic experiments were made by Tamman in 1892, J who" 

 showed that the hydrolysis of, amygdalin and salicin by emulsin is 

 materially retarded in either case on adding any one of the products of 

 their change in advance. 



The effect of glucose on the hydrolysis of maltose by maltase was 

 studied by Croft Hill in 1898.§ The retardation observed was attri- 

 buted by him, perhaps not quite logically, merely to a reverse action 

 by which the glucose underwent conversion into maltose : it may be 

 added that the investigation was undertaken by him from this point of 

 view. 



A more definite step forward was taken by Henri in 1901, who- 

 showed that the retarding effect of invert sugar was mainly due to the 

 fructose, glucose having little or no effect on the action of invertase on 

 cane sugar. Evidence that the effect was due to a specific action of 

 the invert sugar was adduced in the same year by Adrian Brown,|| 

 who showed that whilst the rate of hydrolysis of cane sugar was 

 materially reduced by invert sugar, the corresponding amount of milk 

 sugar had little or no effect, thus precluding the conclusion that the 

 retardation was due to increased viscosity of the liquid. 



In the course of his classic researches on the action of enzymes on the 

 stereochemically related glucosides commenced by Emil Fischer^ in 

 1894, it was clearly established that the closest relationship exists * 

 between the configuration of the hydrolyte and that of the particular 

 enzyme which can affect it. 



In a course of lectures delivered at the Pharmaceutical Society in 1 

 1892,** my father discussed fermentation phenomena generally from, 

 the point of view that hydrolysis was conditioned by the association o£" 



* ' C. K.,' vol. 81, p. 425 and vol. 91, p. 787. 

 f 5 Chem. Soc. Trans.,' vol. 57, p. 919. 

 X 1 Zeit. physiol. Chem.,' vol. 16, p. 291. 

 § ' Chem. Soc. Trans.,' 1898, vol. 23, p. 634. 

 || ' Chem Soc. Trans.,' 1902, vol. 81, p. 373 

 % Summary in 1 Zeit. physiol. Chem.,' vol. 26, p. 60. 

 ** 'Pharmaceutical Journal,' vol., 22, pp. 495, 596, 659, and 757. 



2 o 2; 



